Electrical contact heater



April 1947- A. A. REISER 2,418,557

ELECTRI CAL CONTACT HEATER Filed Oct. 27, 1943 ATTORNEYS Patented Apr. 8, 1947 ELECTRICAL CONTACT HEATER Alfred A. Reiser, Buffalo, N. Y., assignor, by mesne assignments, to Titan Manufacturing Co., 1110., Buffalo, N. Y., a corporation of New York Application October 27, 1943, Serial No. 507,797

3 Claims.

1 h s invention relates to an electrical contact heater and more particularly to a heating unit adapted to be used in a contact heater of the type shown in my co-pending application Serial No. 459,793, filed September 26, 1942, although the heating unit forming the subject of the present application is applicable wherever contact heating is desired.

One of the principal objects of the present invention is to provide a heater unit of the general type shown in my said copending application which can be made at very low cost and can readily be assembled into a holder so as to be held resiliently in contact with the surface to be heated, this resilient connection permittin the unit to adapt itself to the surface to be heated and thereby insure a uniform resilient contact with maximum heat transfer.

Another object of the invention is to employ a resilient material as the thermal insulation for the heating element and to utilize the resiliency of this thermal insulating material to provide the flexibility of the unit in adapting itself to obtain uniformity of contact with the part to be heated.

A further object of the invention is to provide such a contact heater in which the metal outer casing is eliminated and which at the same time firmly holds the heating surface in planar contact with the surface to be heated.

In the accompanying drawings:

Fig. l is a fragmentary vertical section through one form of contact heater embodying my invention and showing the same applied to a surface to be heated.

Fig. 2 is a vertical section through a modified form of contact heater embodying the present invention and showing the same about to be applied to the surface to be heated.

Fig. 3 is a view similar to Fig. 2 showing the contact heater applied to the surface to be heated.

Fig. 4 is a cross section through the quilted asbestos felt used as the resilient backing medium for the heating element.

Fig. 5 is a face view of the quilted asbestos felt used as the resilient backing medium for the heating element.

The form of heating unit shown in Fig. 1 is adapted to be used in connection with a contact heater as shown in my said copending application in which the heating pad or unit, indicated generally at I0, is held against the outer face of a part I l to be heated by means of a sheet metal holder l2 which is yieldingly urged toward the part II to be heated in any suitable manner. This holder I2 is shown as having angle bars l3 secured to its inner face and between which the heating unit or pad I0 is arranged.

The heating unit or pad I0 comprises a cupshaped metal container or shell 15 which can be made of copper or other metal having high heat conductivity, the outer face of this cup-shaped container l5 being held against the outer face of the part II to be heated. Arranged against the inner face of this cupshaped container [5 is a heating element it which can be insulated from the copper shell !5 in any suitable manner and which is supplied with current by means of wires 18. This heating element is shown as being backed by a sheet IQ of insulating material and the remainder of the container or shell I5 is filled with a pad 23 of quilted asbestos felt having both inherent resiliency and also thermal insulating properties.

As best shown in Figs. 4 and "5. the quilted asbestos felt pad. to is made of felted asbestos and can be quilted by means of threads 2| which are passed through the felt body at intervals so as to insure the pad retaining its form. This quilted asbestos pad 26 projectsa substantial distance beyond the rim of the metal shell or container l5 and engages the inner face of the holder 12. The :quilted asbestos pad 20 thereby provides a resilient component between the metal shell or container :5 and the holder !2 so that when the holder 5'? is moved from the dotted line position to the full line position shown in Fig. 1 the metal shell or container 5'5 is free to adapt itself and find uniform resilient contact with the face of the part i i to be heated, thereby to insure maximum heat transfer from the heating element It to the part to be heated. If desired the resiliency of the quilted asbestos pad 29 can be augmented by means of one or more steel springs 22 interposed between this pad and the inner face of the holder iii.

In the form of the invention shown in Figs. 2 and 3 a flexible padof asbestos or like thermal insulation material is utilized both for thermal insulation and also for supporting a heated cupshaped shell or container resiliently against the part to be heated so that this shell is free to adapt itself and. obtain uniform resilient contact with the part to be heated. In this modified form of the invention the cup-shaped shell or container 25 is likewise made of copper or other metal having high thermal conductivity and is shown as housing a resistance element 26 supplied with current from electric lines 21, this resistance element 26 being thermally insulated from the copper shell 25 in any suitable manner.

This resistance element is shown as having a backing sheet 28 of insulating material, and as being set into the face of a quilted asbestos felt pad 29 which is made in the same manner as the quilted asbestos pad 28 shown in Figs. 1, 4 and 5. This pad is, however, substantially larger in outline than the cup-shaped metal shell or container so as to provide a marginal face which surrounds this cup-shaped metal part or container. The sides and outer face of the quilted asbestos pad 29 can be covered with a coating of paint or plastic 3| to provide a rigid structure.

In applying the heating element shown in Figs. 2 and 3 to the part 32 to be heated, the marginal face 30 of the quilted asbestos pad 29 is coated with adhesive cement 3-3. ihe assembly is then pressed against the surface of the part 32 to be heated until the adhesive 33 adheres thereto. In so pressing the unit against the face of the part 32 to be heated, the cup-shaped shell or container 25 is pressed into the body of the quilted asbestos felt pad 29 so that when the adhesive 33 hardens this cup-shaped metal shell or container is firmly and yieldingly held against the face of the part 32 to be heated to obtain good thermal conductivity. Further, in so pressing the unit against the face of the part to be heated, it will be seen that the cup-shaped metal holder or container 25 is free to adapt itself and find uniform resilient contact with the surface to be heated.

From the foregoing it will be seen that the present invention provides a very simple and in expensive form of contact heater in which the quilted asbestos pad or like resilient thermal insulating pad is utilized, both for obtaining thermal insulation and also to insure the proper planar engagement between the metal holder for the heating element and the face of the part to be heated. It will further be seen that the invention can be produced at very low cost and will stand up under conditions of severe and constant operation without getting out of order or requiring repairs.

I claim:

1. An electrical contact heater, comprising a cup-shaped heat conductive member having a face adapted to contact a face of the part to be heated and having its rim projecting in the opposite direction from the margin thereof, an electrical resistance heating element arranged in said cup-shaped member and along the opposite face thereof from that engaging the part to be heated, a pad of compressible material arranged in said cup-shaped member and projecting outwardly therefrom a substantial distance perpendicularly to said faces and also projecting generally parallel with said faces beyond said rim of said cupshaped member, means for exerting pressure against the outwardly projecting part of said pad to hold said cup-shaped member embedded in said pad and. the first face thereof in uniform yielding contact with the said face of the part to be heated, and a coating of a hardening plastic material applied over the exterior of said pad to form a case for the contact heater.

2. An electrical contact heater, comprising a cup-shaped heat conductive member having a face adapted to contact a face of the part to be heated and having its rim projecting in the opposite direction from the margin thereof, an electrical resistance heating element arranged in said cup-shaped member and along the opposite face thereof from that engaging the part to be heated, a pad of compressible material arranged in said cup-shaped member and projecting outwardly therefrom a substantial distance perpendicularly to said faces and also projecting generally parallel with said faces beyond said rim of said cupshaped member, and means for exerting pressure against the outwardly projecting part of said pad to hold said cup-shaped member embedded in said pad and the first face thereof in uniform yielding contact with the said face of the part to be heated, comprising an adhesive uniting the opposin face of said generally parallel projecting part of said pad with the part to be heated.

3. An electrical contact heater, comprising a. cup-shaped heat conductive member having a face adapted to contact a face of the part to be heated and having its rim projecting in the opposite direction from the margin thereof, an elec trical resistance heating element arranged in said cup-shaped member and along the opposite face thereof from that engaging the part to be heated, a pad of compressible material arranged in said cup-shaped member and projecting outwardly therefrom a substantial distance perpendicularly to said faces and also projecting generally parallel with said faces beyond said rim of said cupshaped member, means for exerting pressure against the outwardly projecting part of said pad to hold said cup-shaped member embedded in said pad and the first face thereof in uniform yielding contact with the said face of the part to be heated, comprising an adhesive uniting the opposing face of said generally parallel projecting part of said pad with the part to be heated, and a coating of a hardening plastic material applied over the exterior of said pad to form a case for the contact heater.

ALFRED A. REISER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,869,629 Stranszky Aug. 2, 1932 842,849 Anderson Feb. 5, 1907 1,257,106 Parkhurst Feb. 19, 1918 1,439,121 Reizners Dec. 19, 1922 1,498,684 Day June 24, 1924 FOREIGN PATENTS Number Country Date 390,047 British Mar. 30, 1933 

